[Group 1] Enable nullable annotations for `Microsoft.Extensions.FileSystemGlobbing` (#57398)

* Annotate src

* Annotate ref

* Null check for directoryInfo

* Nullcheck for PatternMatchingResult.Files

* ParentDirectory cannot be null

! need to be addressed

* Update PatternBuilder.cs

* Use expression body in segments

* Update ref

* DisableImplicitAssemblyReferences

* Fix doc

* TestMatchingGroup nonnull

* ParentDirectory can be null

* Update TestGetHashCodeWithNull

* Update FilePatternMatchTests.cs

* Update FilePatternMatchTests.cs

* Remove TestGetHashCodeWithNull

* InMemoryFileInfo.ParentDirectory is not null

src/libraries/Microsoft.Extensions.FileSystemGlobbing/ref/Microsoft.Extensions.FileSystemGlobbing.cs

@@ -10,22 +10,22 @@ public partial struct FilePatternMatch : System.IEquatable<Microsoft.Extensions.
     {
         private object _dummy;
         private int _dummyPrimitive;
-        public FilePatternMatch(string path, string stem) { throw null; }
+        public FilePatternMatch(string path, string? stem) { throw null; }
         public readonly string Path { get { throw null; } }
-        public readonly string Stem { get { throw null; } }
+        public readonly string? Stem { get { throw null; } }
         public bool Equals(Microsoft.Extensions.FileSystemGlobbing.FilePatternMatch other) { throw null; }
-        public override bool Equals(object obj) { throw null; }
+        public override bool Equals([System.Diagnostics.CodeAnalysis.NotNullWhenAttribute(true)] object? obj) { throw null; }
         public override int GetHashCode() { throw null; }
     }
     public partial class InMemoryDirectoryInfo : Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase
     {
-        public InMemoryDirectoryInfo(string rootDir, System.Collections.Generic.IEnumerable<string> files) { }
+        public InMemoryDirectoryInfo(string rootDir, System.Collections.Generic.IEnumerable<string>? files) { }
         public override string FullName { get { throw null; } }
         public override string Name { get { throw null; } }
-        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase ParentDirectory { get { throw null; } }
+        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase? ParentDirectory { get { throw null; } }
         public override System.Collections.Generic.IEnumerable<Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileSystemInfoBase> EnumerateFileSystemInfos() { throw null; }
         public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase GetDirectory(string path) { throw null; }
-        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileInfoBase GetFile(string path) { throw null; }
+        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileInfoBase? GetFile(string path) { throw null; }
     }
     public partial class Matcher
     {
@@ -40,9 +40,9 @@ public static partial class MatcherExtensions
         public static void AddExcludePatterns(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, params System.Collections.Generic.IEnumerable<string>[] excludePatternsGroups) { }
         public static void AddIncludePatterns(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, params System.Collections.Generic.IEnumerable<string>[] includePatternsGroups) { }
         public static System.Collections.Generic.IEnumerable<string> GetResultsInFullPath(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, string directoryPath) { throw null; }
-        public static Microsoft.Extensions.FileSystemGlobbing.PatternMatchingResult Match(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, System.Collections.Generic.IEnumerable<string> files) { throw null; }
+        public static Microsoft.Extensions.FileSystemGlobbing.PatternMatchingResult Match(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, System.Collections.Generic.IEnumerable<string>? files) { throw null; }
         public static Microsoft.Extensions.FileSystemGlobbing.PatternMatchingResult Match(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, string file) { throw null; }
-        public static Microsoft.Extensions.FileSystemGlobbing.PatternMatchingResult Match(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, string rootDir, System.Collections.Generic.IEnumerable<string> files) { throw null; }
+        public static Microsoft.Extensions.FileSystemGlobbing.PatternMatchingResult Match(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, string rootDir, System.Collections.Generic.IEnumerable<string>? files) { throw null; }
         public static Microsoft.Extensions.FileSystemGlobbing.PatternMatchingResult Match(this Microsoft.Extensions.FileSystemGlobbing.Matcher matcher, string rootDir, string file) { throw null; }
     }
     public partial class PatternMatchingResult
@@ -59,17 +59,17 @@ public abstract partial class DirectoryInfoBase : Microsoft.Extensions.FileSyste
     {
         protected DirectoryInfoBase() { }
         public abstract System.Collections.Generic.IEnumerable<Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileSystemInfoBase> EnumerateFileSystemInfos();
-        public abstract Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase GetDirectory(string path);
-        public abstract Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileInfoBase GetFile(string path);
+        public abstract Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase? GetDirectory(string path);
+        public abstract Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileInfoBase? GetFile(string path);
     }
     public partial class DirectoryInfoWrapper : Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase
     {
         public DirectoryInfoWrapper(System.IO.DirectoryInfo directoryInfo) { }
         public override string FullName { get { throw null; } }
         public override string Name { get { throw null; } }
-        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase ParentDirectory { get { throw null; } }
+        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase? ParentDirectory { get { throw null; } }
         public override System.Collections.Generic.IEnumerable<Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileSystemInfoBase> EnumerateFileSystemInfos() { throw null; }
-        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase GetDirectory(string name) { throw null; }
+        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase? GetDirectory(string name) { throw null; }
         public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileInfoBase GetFile(string name) { throw null; }
     }
     public abstract partial class FileInfoBase : Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileSystemInfoBase
@@ -81,14 +81,14 @@ public partial class FileInfoWrapper : Microsoft.Extensions.FileSystemGlobbing.A
         public FileInfoWrapper(System.IO.FileInfo fileInfo) { }
         public override string FullName { get { throw null; } }
         public override string Name { get { throw null; } }
-        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase ParentDirectory { get { throw null; } }
+        public override Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase? ParentDirectory { get { throw null; } }
     }
     public abstract partial class FileSystemInfoBase
     {
         protected FileSystemInfoBase() { }
         public abstract string FullName { get; }
         public abstract string Name { get; }
-        public abstract Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase ParentDirectory { get; }
+        public abstract Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase? ParentDirectory { get; }
     }
 }
 namespace Microsoft.Extensions.FileSystemGlobbing.Internal
@@ -133,8 +133,8 @@ public partial struct PatternTestResult
         private int _dummyPrimitive;
         public static readonly Microsoft.Extensions.FileSystemGlobbing.Internal.PatternTestResult Failed;
         public readonly bool IsSuccessful { get { throw null; } }
-        public readonly string Stem { get { throw null; } }
-        public static Microsoft.Extensions.FileSystemGlobbing.Internal.PatternTestResult Success(string stem) { throw null; }
+        public readonly string? Stem { get { throw null; } }
+        public static Microsoft.Extensions.FileSystemGlobbing.Internal.PatternTestResult Success(string? stem) { throw null; }
     }
 }
 namespace Microsoft.Extensions.FileSystemGlobbing.Internal.PathSegments
@@ -150,7 +150,7 @@ public partial class LiteralPathSegment : Microsoft.Extensions.FileSystemGlobbin
         public LiteralPathSegment(string value, System.StringComparison comparisonType) { }
         public bool CanProduceStem { get { throw null; } }
         public string Value { get { throw null; } }
-        public override bool Equals(object obj) { throw null; }
+        public override bool Equals([System.Diagnostics.CodeAnalysis.NotNullWhenAttribute(true)] object? obj) { throw null; }
         public override int GetHashCode() { throw null; }
         public bool Match(string value) { throw null; }
     }
@@ -195,7 +195,7 @@ public partial struct FrameData
             public bool InStem;
             public bool IsNotApplicable;
             public int SegmentIndex;
-            public string Stem { get { throw null; } }
+            public string? Stem { get { throw null; } }
             public System.Collections.Generic.IList<string> StemItems { get { throw null; } }
         }
     }
@@ -232,7 +232,7 @@ public partial struct FrameData
             public System.Collections.Generic.IList<Microsoft.Extensions.FileSystemGlobbing.Internal.IPathSegment> SegmentGroup;
             public int SegmentGroupIndex;
             public int SegmentIndex;
-            public string Stem { get { throw null; } }
+            public string? Stem { get { throw null; } }
             public System.Collections.Generic.IList<string> StemItems { get { throw null; } }
         }
     }
@@ -249,12 +249,12 @@ public partial class PatternContextRaggedInclude : Microsoft.Extensions.FileSyst
     }
     public abstract partial class PatternContext<TFrame> : Microsoft.Extensions.FileSystemGlobbing.Internal.IPatternContext
     {
-        protected TFrame Frame;
+        protected TFrame? Frame;
         protected PatternContext() { }
         public virtual void Declare(System.Action<Microsoft.Extensions.FileSystemGlobbing.Internal.IPathSegment, bool> declare) { }
         protected bool IsStackEmpty() { throw null; }
         public virtual void PopDirectory() { }
-        protected void PushDataFrame(TFrame frame) { }
+        protected void PushDataFrame(TFrame? frame) { }
         public abstract void PushDirectory(Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase directory);
         public abstract bool Test(Microsoft.Extensions.FileSystemGlobbing.Abstractions.DirectoryInfoBase directory);
         public abstract Microsoft.Extensions.FileSystemGlobbing.Internal.PatternTestResult Test(Microsoft.Extensions.FileSystemGlobbing.Abstractions.FileInfoBase file);

src/libraries/Microsoft.Extensions.FileSystemGlobbing/ref/Microsoft.Extensions.FileSystemGlobbing.csproj

 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppMinimum);netstandard2.0;$(NetFrameworkMinimum)</TargetFrameworks>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="Microsoft.Extensions.FileSystemGlobbing.cs" />

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Abstractions/DirectoryInfoBase.cs

@@ -21,13 +21,13 @@ public abstract class DirectoryInfoBase : FileSystemInfoBase
         /// </summary>
         /// <param name="path">The directory name</param>
         /// <returns>Instance of <see cref="DirectoryInfoBase" /> even if directory does not exist</returns>
-        public abstract DirectoryInfoBase GetDirectory(string path);
+        public abstract DirectoryInfoBase? GetDirectory(string path);
 
         /// <summary>
         /// Returns an instance of <see cref="FileInfoBase" /> that represents a file in the directory
         /// </summary>
         /// <param name="path">The file name</param>
         /// <returns>Instance of <see cref="FileInfoBase" /> even if file does not exist</returns>
-        public abstract FileInfoBase GetFile(string path);
+        public abstract FileInfoBase? GetFile(string path);
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Abstractions/DirectoryInfoWrapper.cs

@@ -47,8 +47,7 @@ public override IEnumerable<FileSystemInfoBase> EnumerateFileSystemInfos()
 
                 foreach (FileSystemInfo fileSystemInfo in fileSystemInfos)
                 {
-                    var directoryInfo = fileSystemInfo as DirectoryInfo;
-                    if (directoryInfo != null)
+                    if (fileSystemInfo is DirectoryInfo directoryInfo)
                     {
                         yield return new DirectoryInfoWrapper(directoryInfo);
                     }
@@ -68,7 +67,7 @@ public override IEnumerable<FileSystemInfoBase> EnumerateFileSystemInfos()
         /// </remarks>
         /// <param name="name">The directory name</param>
         /// <returns>The directory</returns>
-        public override DirectoryInfoBase GetDirectory(string name)
+        public override DirectoryInfoBase? GetDirectory(string name)
         {
             bool isParentPath = string.Equals(name, "..", StringComparison.Ordinal);
 
@@ -120,7 +119,7 @@ public override FileInfoBase GetFile(string name)
         /// <remarks>
         /// Equals the value of <seealso cref="System.IO.DirectoryInfo.Parent" />.
         /// </remarks>
-        public override DirectoryInfoBase ParentDirectory
-            => new DirectoryInfoWrapper(_directoryInfo.Parent);
+        public override DirectoryInfoBase? ParentDirectory
+            => new DirectoryInfoWrapper(_directoryInfo.Parent!);
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Abstractions/FileInfoWrapper.cs

 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.IO;
 
 namespace Microsoft.Extensions.FileSystemGlobbing.Abstractions
@@ -18,7 +19,7 @@ public class FileInfoWrapper : FileInfoBase
         /// <param name="fileInfo">The <see cref="System.IO.FileInfo" /></param>
         public FileInfoWrapper(FileInfo fileInfo)
         {
-            _fileInfo = fileInfo;
+            _fileInfo = fileInfo ?? throw new ArgumentNullException(nameof(fileInfo));
         }
 
         /// <summary>
@@ -43,6 +44,7 @@ public FileInfoWrapper(FileInfo fileInfo)
         /// <remarks>
         /// Equals the value of <see cref="System.IO.FileInfo.Directory" />.
         /// </remarks>
-        public override DirectoryInfoBase ParentDirectory => new DirectoryInfoWrapper(_fileInfo.Directory);
+        public override DirectoryInfoBase? ParentDirectory
+            => new DirectoryInfoWrapper(_fileInfo.Directory!);
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Abstractions/FileSystemInfoBase.cs

@@ -21,6 +21,6 @@ public abstract class FileSystemInfoBase
         /// <summary>
         /// The parent directory for the current file or directory
         /// </summary>
-        public abstract DirectoryInfoBase ParentDirectory { get; }
+        public abstract DirectoryInfoBase? ParentDirectory { get; }
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/FilePatternMatch.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Numerics.Hashing;
 
 namespace Microsoft.Extensions.FileSystemGlobbing
@@ -27,16 +28,16 @@ public struct FilePatternMatch : IEquatable<FilePatternMatch>
         /// If the matcher searched for "src/Project/**/*.cs" and the pattern matcher found "src/Project/Interfaces/IFile.cs",
         /// then <see cref="Stem" /> = "Interfaces/IFile.cs" and <see cref="Path" /> = "src/Project/Interfaces/IFile.cs".
         /// </remarks>
-        public string Stem { get; }
+        public string? Stem { get; }
 
         /// <summary>
         /// Initializes new instance of <see cref="FilePatternMatch" />
         /// </summary>
         /// <param name="path">The path to the file matched, relative to the beginning of the matching search pattern.</param>
         /// <param name="stem">The subpath to the file matched, relative to the first wildcard in the matching search pattern.</param>
-        public FilePatternMatch(string path, string stem)
+        public FilePatternMatch(string path, string? stem)
         {
-            Path = path;
+            Path = path ?? throw new ArgumentNullException(nameof(path));
             Stem = stem;
         }
 
@@ -56,10 +57,8 @@ public bool Equals(FilePatternMatch other)
         /// </summary>
         /// <param name="obj">The object to be compared</param>
         /// <returns>True when <see cref="Equals(FilePatternMatch)" /></returns>
-        public override bool Equals(object obj)
-        {
-            return Equals((FilePatternMatch) obj);
-        }
+        public override bool Equals([NotNullWhen(true)] object? obj) =>
+            obj is FilePatternMatch match && Equals(match);
 
         /// <summary>
         /// Gets a hash for the file pattern match.
@@ -68,7 +67,7 @@ public override bool Equals(object obj)
         public override int GetHashCode() =>
             HashHelpers.Combine(GetHashCode(Path), GetHashCode(Stem));
 
-        private static int GetHashCode(string value) =>
+        private static int GetHashCode(string? value) =>
             value != null ? StringComparer.OrdinalIgnoreCase.GetHashCode(value) : 0;
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/InMemoryDirectoryInfo.cs

@@ -23,22 +23,19 @@ public class InMemoryDirectoryInfo : DirectoryInfoBase
         /// </summary>
         /// <param name="rootDir">The root directory that this FileSystem will use.</param>
         /// <param name="files">Collection of file names. If relative paths <paramref name="rootDir"/> will be prepended to the paths.</param>
-        public InMemoryDirectoryInfo(string rootDir, IEnumerable<string> files)
+        public InMemoryDirectoryInfo(string rootDir, IEnumerable<string>? files)
             : this(rootDir, files, false)
         {
         }
 
-        private InMemoryDirectoryInfo(string rootDir, IEnumerable<string> files, bool normalized)
+        private InMemoryDirectoryInfo(string rootDir, IEnumerable<string>? files, bool normalized)
         {
             if (string.IsNullOrEmpty(rootDir))
             {
                 throw new ArgumentNullException(nameof(rootDir));
             }
 
-            if (files == null)
-            {
-                files = new List<string>();
-            }
+            files ??= new List<string>();
 
             Name = Path.GetFileName(rootDir);
             if (normalized)
@@ -69,13 +66,8 @@ private InMemoryDirectoryInfo(string rootDir, IEnumerable<string> files, bool no
         public override string Name { get; }
 
         /// <inheritdoc />
-        public override DirectoryInfoBase ParentDirectory
-        {
-            get
-            {
-                return new InMemoryDirectoryInfo(Path.GetDirectoryName(FullName), _files, true);
-            }
-        }
+        public override DirectoryInfoBase? ParentDirectory =>
+            new InMemoryDirectoryInfo(Path.GetDirectoryName(FullName)!, _files, true);
 
         /// <inheritdoc />
         public override IEnumerable<FileSystemInfoBase> EnumerateFileSystemInfos()
@@ -99,8 +91,7 @@ public override IEnumerable<FileSystemInfoBase> EnumerateFileSystemInfos()
                 else
                 {
                     string name = file.Substring(0, endSegment);
-                    List<string> list;
-                    if (!dict.TryGetValue(name, out list))
+                    if (!dict.TryGetValue(name, out List<string>? list))
                     {
                         dict[name] = new List<string> { file };
                     }
@@ -145,7 +136,7 @@ public override DirectoryInfoBase GetDirectory(string path)
         /// </summary>
         /// <param name="path">The filename.</param>
         /// <returns>Instance of <see cref="FileInfoBase"/> if the file exists, null otherwise.</returns>
-        public override FileInfoBase GetFile(string path)
+        public override FileInfoBase? GetFile(string path)
         {
             string normPath = Path.GetFullPath(path.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar));
             foreach (string file in _files)

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/InMemoryFileInfo.cs

@@ -21,12 +21,6 @@ public InMemoryFileInfo(string file, InMemoryDirectoryInfo parent)
 
         public override string Name { get; }
 
-        public override DirectoryInfoBase ParentDirectory
-        {
-            get
-            {
-                return _parent;
-            }
-        }
+        public override DirectoryInfoBase ParentDirectory => _parent;
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/MatcherContext.cs

@@ -55,13 +55,13 @@ public PatternMatchingResult Execute()
             return new PatternMatchingResult(_files, _files.Count > 0);
         }
 
-        private void Match(DirectoryInfoBase directory, string parentRelativePath)
+        private void Match(DirectoryInfoBase directory, string? parentRelativePath)
         {
             // Request all the including and excluding patterns to push current directory onto their status stack.
             PushDirectory(directory);
             Declare();
 
-            var entities = new List<FileSystemInfoBase>();
+            var entities = new List<FileSystemInfoBase?>();
             if (_declaredWildcardPathSegment || _declaredLiteralFileSegments.Any())
             {
                 entities.AddRange(directory.EnumerateFileSystemInfos());
@@ -85,10 +85,9 @@ private void Match(DirectoryInfoBase directory, string parentRelativePath)
 
             // collect files and sub directories
             var subDirectories = new List<DirectoryInfoBase>();
-            foreach (FileSystemInfoBase entity in entities)
+            foreach (FileSystemInfoBase? entity in entities)
             {
-                var fileInfo = entity as FileInfoBase;
-                if (fileInfo != null)
+                if (entity is FileInfoBase fileInfo)
                 {
                     PatternTestResult result = MatchPatternContexts(fileInfo, (pattern, file) => pattern.Test(file));
                     if (result.IsSuccessful)
@@ -101,8 +100,7 @@ private void Match(DirectoryInfoBase directory, string parentRelativePath)
                     continue;
                 }
 
-                var directoryInfo = entity as DirectoryInfoBase;
-                if (directoryInfo != null)
+                if (entity is DirectoryInfoBase directoryInfo)
                 {
                     if (MatchPatternContexts(directoryInfo, (pattern, dir) => pattern.Test(dir)))
                     {
@@ -140,8 +138,7 @@ private void Declare()
 
         private void DeclareInclude(IPathSegment patternSegment, bool isLastSegment)
         {
-            var literalSegment = patternSegment as LiteralPathSegment;
-            if (literalSegment != null)
+            if (patternSegment is LiteralPathSegment literalSegment)
             {
                 if (isLastSegment)
                 {
@@ -163,7 +160,7 @@ private void DeclareInclude(IPathSegment patternSegment, bool isLastSegment)
             }
         }
 
-        internal static string CombinePath(string left, string right)
+        internal static string CombinePath(string? left, string right)
         {
             if (string.IsNullOrEmpty(left))
             {

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PathSegments/CurrentPathSegment.cs

@@ -7,11 +7,8 @@ namespace Microsoft.Extensions.FileSystemGlobbing.Internal.PathSegments
 {
     public class CurrentPathSegment : IPathSegment
     {
-        public bool CanProduceStem { get { return false; } }
+        public bool CanProduceStem => false;
 
-        public bool Match(string value)
-        {
-            return false;
-        }
+        public bool Match(string value) => false;
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PathSegments/LiteralPathSegment.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using Microsoft.Extensions.FileSystemGlobbing.Util;
 
 namespace Microsoft.Extensions.FileSystemGlobbing.Internal.PathSegments
@@ -10,16 +11,11 @@ public class LiteralPathSegment : IPathSegment
     {
         private readonly StringComparison _comparisonType;
 
-        public bool CanProduceStem { get { return false; } }
+        public bool CanProduceStem => false;
 
         public LiteralPathSegment(string value, StringComparison comparisonType)
         {
-            if (value == null)
-            {
-                throw new ArgumentNullException(nameof(value));
-            }
-
-            Value = value;
+            Value = value ?? throw new ArgumentNullException(nameof(value));
 
             _comparisonType = comparisonType;
         }
@@ -31,11 +27,9 @@ public bool Match(string value)
             return string.Equals(Value, value, _comparisonType);
         }
 
-        public override bool Equals(object obj)
+        public override bool Equals([NotNullWhen(true)] object? obj)
         {
-            var other = obj as LiteralPathSegment;
-
-            return other != null &&
+            return obj is LiteralPathSegment other &&
                 _comparisonType == other._comparisonType &&
                 string.Equals(other.Value, Value, _comparisonType);
         }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PathSegments/ParentPathSegment.cs

@@ -9,7 +9,7 @@ public class ParentPathSegment : IPathSegment
     {
         private const string LiteralParent = "..";
 
-        public bool CanProduceStem { get { return false; } }
+        public bool CanProduceStem => false;
 
         public bool Match(string value)
         {

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PathSegments/RecursiveWildcardSegment.cs

@@ -7,11 +7,8 @@ namespace Microsoft.Extensions.FileSystemGlobbing.Internal.PathSegments
 {
     public class RecursiveWildcardSegment : IPathSegment
     {
-        public bool CanProduceStem { get { return true; } }
+        public bool CanProduceStem => true;
 
-        public bool Match(string value)
-        {
-            return false;
-        }
+        public bool Match(string value) => false;
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PathSegments/WildcardPathSegment.cs

@@ -17,9 +17,9 @@ public class WildcardPathSegment : IPathSegment
 
         public WildcardPathSegment(string beginsWith, List<string> contains, string endsWith, StringComparison comparisonType)
         {
-            BeginsWith = beginsWith;
-            Contains = contains;
-            EndsWith = endsWith;
+            BeginsWith = beginsWith ?? throw new ArgumentNullException(nameof(beginsWith));
+            Contains = contains ?? throw new ArgumentNullException(nameof(contains));
+            EndsWith = endsWith ?? throw new ArgumentNullException(nameof(endsWith));
             _comparisonType = comparisonType;
         }
 

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PatternContexts/PatternContext.cs

@@ -9,8 +9,8 @@ namespace Microsoft.Extensions.FileSystemGlobbing.Internal.PatternContexts
 {
     public abstract class PatternContext<TFrame> : IPatternContext
     {
-        private Stack<TFrame> _stack = new Stack<TFrame>();
-        protected TFrame Frame;
+        private Stack<TFrame?> _stack = new();
+        protected TFrame? Frame;
 
         public virtual void Declare(Action<IPathSegment, bool> declare) { }
 
@@ -25,7 +25,7 @@ public virtual void PopDirectory()
             Frame = _stack.Pop();
         }
 
-        protected void PushDataFrame(TFrame frame)
+        protected void PushDataFrame(TFrame? frame)
         {
             _stack.Push(Frame);
             Frame = frame;

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PatternContexts/PatternContextLinear.cs

@@ -12,7 +12,7 @@ public abstract class PatternContextLinear
     {
         public PatternContextLinear(ILinearPattern pattern)
         {
-            Pattern = pattern;
+            Pattern = pattern ?? throw new ArgumentNullException(nameof(pattern));
         }
 
         public override PatternTestResult Test(FileInfoBase file)
@@ -67,17 +67,11 @@ public struct FrameData
             public bool IsNotApplicable;
             public int SegmentIndex;
             public bool InStem;
-            private IList<string> _stemItems;
+            private IList<string>? _stemItems;
 
-            public IList<string> StemItems
-            {
-                get { return _stemItems ?? (_stemItems = new List<string>()); }
-            }
+            public IList<string> StemItems => _stemItems ??= new List<string>();
 
-            public string Stem
-            {
-                get { return _stemItems == null ? null : string.Join("/", _stemItems); }
-            }
+            public string? Stem => _stemItems == null ? null : string.Join("/", _stemItems);
         }
 
         protected ILinearPattern Pattern { get; }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PatternContexts/PatternContextRagged.cs

@@ -11,7 +11,7 @@ public abstract class PatternContextRagged : PatternContext<PatternContextRagged
     {
         public PatternContextRagged(IRaggedPattern pattern)
         {
-            Pattern = pattern;
+            Pattern = pattern ?? throw new ArgumentNullException(nameof(pattern));
         }
 
         public override PatternTestResult Test(FileInfoBase file)
@@ -122,17 +122,11 @@ public struct FrameData
 
             public bool InStem;
 
-            private IList<string> _stemItems;
+            private IList<string>? _stemItems;
 
-            public IList<string> StemItems
-            {
-                get { return _stemItems ?? (_stemItems = new List<string>()); }
-            }
+            public IList<string> StemItems => _stemItems ??= new List<string>();
 
-            public string Stem
-            {
-                get { return _stemItems == null ? null : string.Join("/", _stemItems); }
-            }
+            public string? Stem => _stemItems == null ? null : string.Join("/", _stemItems);
         }
 
         protected IRaggedPattern Pattern { get; }
@@ -165,11 +159,11 @@ protected bool TestMatchingGroup(FileSystemInfoBase value)
                 return false;
             }
 
-            FileSystemInfoBase scan = value;
+            FileSystemInfoBase? scan = value;
             for (int index = 0; index != groupLength; ++index)
             {
                 IPathSegment segment = Frame.SegmentGroup[groupLength - index - 1];
-                if (!segment.Match(scan.Name))
+                if (scan == null || !segment.Match(scan.Name))
                 {
                     return false;
                 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/PatternTestResult.cs

@@ -9,18 +9,18 @@ namespace Microsoft.Extensions.FileSystemGlobbing.Internal
     /// </summary>
     public struct PatternTestResult
     {
-        public static readonly PatternTestResult Failed = new PatternTestResult(isSuccessful: false, stem: null);
+        public static readonly PatternTestResult Failed = new(isSuccessful: false, stem: null);
 
         public bool IsSuccessful { get; }
-        public string Stem { get; }
+        public string? Stem { get; }
 
-        private PatternTestResult(bool isSuccessful, string stem)
+        private PatternTestResult(bool isSuccessful, string? stem)
         {
             IsSuccessful = isSuccessful;
             Stem = stem;
         }
 
-        public static PatternTestResult Success(string stem)
+        public static PatternTestResult Success(string? stem)
         {
             return new PatternTestResult(isSuccessful: true, stem: stem);
         }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Internal/Patterns/PatternBuilder.cs

@@ -44,9 +44,9 @@ public IPattern Build(string pattern)
             var allSegments = new List<IPathSegment>();
             bool isParentSegmentLegal = true;
 
-            IList<IPathSegment> segmentsPatternStartsWith = null;
-            IList<IList<IPathSegment>> segmentsPatternContains = null;
-            IList<IPathSegment> segmentsPatternEndsWith = null;
+            IList<IPathSegment>? segmentsPatternStartsWith = null;
+            IList<IList<IPathSegment>>? segmentsPatternContains = null;
+            IList<IPathSegment>? segmentsPatternEndsWith = null;
 
             int endPattern = pattern.Length;
             for (int scanPattern = 0; scanPattern < endPattern;)
@@ -54,7 +54,7 @@ public IPattern Build(string pattern)
                 int beginSegment = scanPattern;
                 int endSegment = NextIndex(pattern, _slashes, scanPattern, endPattern);
 
-                IPathSegment segment = null;
+                IPathSegment? segment = null;
 
                 if (segment == null && endSegment - beginSegment == 3)
                 {
@@ -163,7 +163,7 @@ public IPattern Build(string pattern)
                     }
                 }
 
-                if (!(segment is ParentPathSegment))
+                if (segment is not ParentPathSegment)
                 {
                     isParentSegmentLegal = false;
                 }
@@ -182,9 +182,9 @@ public IPattern Build(string pattern)
                             segmentsPatternEndsWith = new List<IPathSegment>();
                             segmentsPatternContains = new List<IList<IPathSegment>>();
                         }
-                        else if (segmentsPatternEndsWith.Count != 0)
+                        else if (segmentsPatternEndsWith!.Count != 0)
                         {
-                            segmentsPatternContains.Add(segmentsPatternEndsWith);
+                            segmentsPatternContains!.Add(segmentsPatternEndsWith);
                             segmentsPatternEndsWith = new List<IPathSegment>();
                         }
                     }
@@ -205,7 +205,7 @@ public IPattern Build(string pattern)
             }
             else
             {
-                return new RaggedPattern(allSegments, segmentsPatternStartsWith, segmentsPatternEndsWith, segmentsPatternContains);
+                return new RaggedPattern(allSegments, segmentsPatternStartsWith, segmentsPatternEndsWith!, segmentsPatternContains!);
             }
         }
 

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Matcher.cs

@@ -159,9 +159,14 @@ public virtual Matcher AddExclude(string pattern)
         /// Searches the directory specified for all files matching patterns added to this instance of <see cref="Matcher" />
         /// </summary>
         /// <param name="directoryInfo">The root directory for the search</param>
-        /// <returns>Always returns instance of <see cref="PatternMatchingResult" />, even if not files were matched</returns>
+        /// <returns>Always returns instance of <see cref="PatternMatchingResult" />, even if no files were matched</returns>
         public virtual PatternMatchingResult Execute(DirectoryInfoBase directoryInfo)
         {
+            if (directoryInfo is null)
+            {
+                throw new ArgumentNullException(nameof(directoryInfo));
+            }
+
             var context = new MatcherContext(_includePatterns, _excludePatterns, directoryInfo, _comparison);
             return context.Execute();
         }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/MatcherExtensions.cs

@@ -86,7 +86,7 @@ public static PatternMatchingResult Match(this Matcher matcher, string rootDir,
         /// <param name="matcher">The matcher that holds the patterns and pattern matching type.</param>
         /// <param name="files">The files to run the matcher against.</param>
         /// <returns>The match results.</returns>
-        public static PatternMatchingResult Match(this Matcher matcher, IEnumerable<string> files)
+        public static PatternMatchingResult Match(this Matcher matcher, IEnumerable<string>? files)
         {
             return Match(matcher, Directory.GetCurrentDirectory(), files);
         }
@@ -98,7 +98,7 @@ public static PatternMatchingResult Match(this Matcher matcher, IEnumerable<stri
         /// <param name="rootDir">The root directory for the matcher to match the files from.</param>
         /// <param name="files">The files to run the matcher against.</param>
         /// <returns>The match results.</returns>
-        public static PatternMatchingResult Match(this Matcher matcher, string rootDir, IEnumerable<string> files)
+        public static PatternMatchingResult Match(this Matcher matcher, string rootDir, IEnumerable<string>? files)
         {
             if (matcher == null)
             {

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Microsoft.Extensions.FileSystemGlobbing.csproj

@@ -2,7 +2,10 @@
 
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppMinimum);netstandard2.0;$(NetFrameworkMinimum)</TargetFrameworks>
+    <Nullable>enable</Nullable>
     <EnableDefaultItems>true</EnableDefaultItems>
+    <!-- Use targeting pack references instead of granular ones in the project file. -->
+    <DisableImplicitAssemblyReferences>false</DisableImplicitAssemblyReferences>
     <PackageDescription>File system globbing to find files matching a specified pattern.</PackageDescription>
   </PropertyGroup>
 
@@ -10,10 +13,5 @@
     <Compile Include="$(CoreLibSharedDir)\System\Numerics\Hashing\HashHelpers.cs"
              Link="System\Numerics\Hashing\HashHelpers.cs" />
   </ItemGroup>
-  
-  <ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'">
-    <Reference Include="System.Collections" />
-    <Reference Include="System.Linq" />
-    <Reference Include="System.Runtime" />
-  </ItemGroup>
+
 </Project>

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/PatternMatchingResult.cs

 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -28,7 +29,7 @@ public PatternMatchingResult(IEnumerable<FilePatternMatch> files)
         /// <param name="hasMatches">A value that determines if <see cref="PatternMatchingResult"/> has any matches.</param>
         public PatternMatchingResult(IEnumerable<FilePatternMatch> files, bool hasMatches)
         {
-            Files = files;
+            Files = files ?? throw new ArgumentNullException(nameof(files));
             HasMatches = hasMatches;
         }
 

src/libraries/Microsoft.Extensions.FileSystemGlobbing/src/Util/StringComparisonHelper.cs

@@ -7,25 +7,15 @@ namespace Microsoft.Extensions.FileSystemGlobbing.Util
 {
     internal static class StringComparisonHelper
     {
-        public static StringComparer GetStringComparer(StringComparison comparisonType)
+        public static StringComparer GetStringComparer(StringComparison comparisonType) => comparisonType switch
         {
-            switch (comparisonType)
-            {
-                case StringComparison.CurrentCulture:
-                    return StringComparer.CurrentCulture;
-                case StringComparison.CurrentCultureIgnoreCase:
-                    return StringComparer.CurrentCultureIgnoreCase;
-                case StringComparison.Ordinal:
-                    return StringComparer.Ordinal;
-                case StringComparison.OrdinalIgnoreCase:
-                    return StringComparer.OrdinalIgnoreCase;
-                case StringComparison.InvariantCulture:
-                    return StringComparer.InvariantCulture;
-                case StringComparison.InvariantCultureIgnoreCase:
-                    return StringComparer.InvariantCultureIgnoreCase;
-                default:
-                    throw new InvalidOperationException(SR.Format(SR.UnexpectedStringComparisonType, comparisonType));
-            }
-        }
+            StringComparison.CurrentCulture => StringComparer.CurrentCulture,
+            StringComparison.CurrentCultureIgnoreCase => StringComparer.CurrentCultureIgnoreCase,
+            StringComparison.Ordinal => StringComparer.Ordinal,
+            StringComparison.OrdinalIgnoreCase => StringComparer.OrdinalIgnoreCase,
+            StringComparison.InvariantCulture => StringComparer.InvariantCulture,
+            StringComparison.InvariantCultureIgnoreCase => StringComparer.InvariantCultureIgnoreCase,
+            _ => throw new InvalidOperationException(SR.Format(SR.UnexpectedStringComparisonType, comparisonType))
+        };
     }
 }

src/libraries/Microsoft.Extensions.FileSystemGlobbing/tests/FilePatternMatchTests.cs

@@ -24,18 +24,5 @@ public void TestGetHashCode()
             FilePatternMatch matchCase2 = new FilePatternMatch("sub/sub2/bar/baz/three.txt", "Sub2/bar/baz/thrEE.txt");
             Assert.Equal(matchCase1.GetHashCode(), matchCase2.GetHashCode());
         }
-
-        [Fact]
-        public void TestGetHashCodeWithNull()
-        {
-            FilePatternMatch match = new FilePatternMatch(null, null);
-            Assert.Equal(0, match.GetHashCode());
-
-            int hash1 = new FilePatternMatch("non null", null).GetHashCode();
-            int hash2 = new FilePatternMatch(null, "non null").GetHashCode();
-            Assert.NotEqual(0, hash1);
-            Assert.NotEqual(0, hash2);
-            Assert.NotEqual(hash1, hash2);
-        }
     }
 }